In the retail industry, flat bed, laser-based readers, also known as horizontal slot scanners, have been used to electro-optically read one-dimensional bar code symbols, particularly of the Universal Product Code (UPC) type, at point-of-transaction checkout systems in supermarkets, warehouse clubs, department stores, and other kinds of retailers for many years. As exemplified by U.S. Pat. No. 5,059,779; No. 5,124,539 and No. 5,200,599, a single, horizontal window is set flush with, and built into, a horizontal countertop of the system. Products to be purchased bear identifying symbols and are typically slid by a clerk across the horizontal window through which a multitude of scan lines is projected in a generally upwards direction. When at least one of the scan lines sweeps over a symbol associated with a product, the symbol is processed and read. The multitude of scan lines is typically generated by a scan pattern generator which includes a laser for emitting a laser beam at a mirrored component mounted on a shaft for rotation by a motor about an axis. A plurality of stationary mirrors is arranged about the axis. As the mirrored component turns, the laser beam is successively reflected onto the stationary mirrors for reflection therefrom through the horizontal window as a scan pattern of the scan lines.
It is also known to provide a checkout system not only with a generally horizontal window, but also with an upright or generally vertical window that faces the clerk at the system. The upright window is oriented generally perpendicularly to the horizontal window, or is slightly rearwardly or forwardly inclined. The laser scan pattern generator within this dual window or bi-optical terminal or workstation also projects the multitude of scan lines in a generally outward direction through the upright window toward the clerk. The generator for the upright window can be the same as, or different from, the generator for the horizontal window. The clerk slides the products past either window, e.g., from right to left, or from left to right, or diagonally, in a “swipe” mode. Alternatively, the clerk merely presents the symbol on the product to a central region of either window in a “presentation” mode. The choice depends on clerk preference or on the layout of the system.
Sometimes, the upright window is not built into the system as a permanent installation. Instead, a vertical slot scanner is configured as a portable reader that is placed on the countertop of an existing horizontal slot scanner in a hands-free mode of operation. In the frequent event that large, heavy, or bulky products, which cannot easily be brought to the reader, have symbols that are required to be read, then the clerk may also manually grasp the portable reader and lift it off, and remove it from, the countertop for reading the symbols in a handheld mode of operation.
As advantageous as these laser-based, point-of-transaction systems have been in processing transactions involving products associated with one-dimensional symbols, each having a row of bars and spaces spaced apart along one direction, these systems cannot process stacked symbols, such as Code 49 that introduced the concept of vertically stacking a plurality of rows of bar and space patterns in a single symbol, as described in U.S. Pat. No. 4,794,239, or two-dimensional symbols, such as PDF417 that increased the amount of data that could be represented or stored on a given amount of surface area, as described in U.S. Pat. No. 5,304,786. Both one- and two-dimensional symbols, as well as stacked symbols, can be read by employing imaging readers each having a solid-state imager which has a one- or two-dimensional array of cells or photosensors that correspond to image elements or pixels in a field of view of the imager. Such an imager may include a one- or two-dimensional charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS) device, as well as associated circuits for producing electronic signals corresponding to the one- or two-dimensional array of pixel information over the field of view.
It is therefore known to use a solid-state imager for capturing a monochrome image of a symbol as, for example, disclosed in U.S. Pat. No. 5,703,349. It is also known to use a solid-state imager with multiple buried channels for capturing a full color image of a target as, for example, disclosed in U.S. Pat. No. 4,613,895. It is common to provide a two-dimensional CCD with a 640×480 resolution commonly found in VGA monitors, although other resolution sizes are possible.
It is also known to install the solid-state imager, analogous to that conventionally used in a consumer digital camera, in a bi-optical, point-of-transaction workstation, as disclosed in U.S. Pat. No. 7,191,947, in which the dual use of both the solid-state imager and the laser scan pattern generator in the same workstation is disclosed. It is possible to replace all of the laser scan pattern generators with solid-state imagers in order to improve reliability and to enable the reading of two-dimensional and stacked symbols, as well as the imaging of other targets, such as signatures, driver's licenses, receipts, etc.
As advantageous as the known laser- and/or imager-based, bi-optical workstations have been in processing products, the workstations are often accompanied by auxiliary electro-optical readers, either laser-based or imager-based, operated in a handheld mode to facilitate reading of large, heavy or bulky items that cannot be readily lifted into position facing at least one of the windows of a respective workstation. In general, a corded reader is used, and its cord or cable is plugged directly into an auxiliary reader port on the workstation. The corded reader when not held in one's hand can be supported in a convenience stand mounted on the countertop at which the workstation is mounted, or can be placed directly on the countertop. However, the corded reader's cable typically gets in the way of the handling of the products to be processed at the workstation, and the cable must often be repeatedly pushed out of the way after each time the corded reader is used. In addition, should the corded reader or its cable become damaged, the workstation must be removed from the countertop to enable unplugging of the corded reader for repair or replacement.
To alleviate part of this problem caused by the presence of the cable, a cordless reader can be operated in a handheld mode. The cordless reader is typically supported in a hands-free mode by a base station mounted on the countertop. When in the base station, the cordless reader's on-board batteries are electrically recharged by an external power supply connected to the base station. The base station also may contain a wireless transceiver with which an on-board wireless transceiver in the cordless reader communicates when a symbol on a product is read, as well as interface circuitry compatible with the auxiliary reader port on the workstation.
Although this cordless arrangement avoids the problem with the reader's cable being in the way and possibly becoming damaged, the base station/cordless reader combination is expensive, requires an external power supply and interface circuitry, and occupies a relatively large of space, or large footprint, on the countertop, often already crowded with other products and equipment, such as a cash register, a credit/debit card reader, a receipt printer, a keyboard, a display, a scale, bagging items, etc. In fact, some countertops, especially in small convenience stores, are so small to begin with that it is difficult to find a free place to position the base station, where the base station won't physically interfere with the operation of the workstation, and which is still convenient for the operator to reach when the cordless reader is needed.
Accordingly, a solution is needed that eliminates the inconvenience and minimizes the expense of a cordless reader, that eliminates the external power supply, and that reduces the size of the footprint on the countertop as compared to that of a conventional cordless reader with a base station. An additional problem that requires a solution is that the known cordless readers can easily become lost or stolen, or their batteries can be discharged during a work shift if their users neglect to replace them back on their respective/base stations. A means of assuring that the cordless reader is always returned to its base station when not in use is thus needed.